We confirm fast regeneration kinetics between copper complexes and oxidized organic dyes and the major contribution of electronic coupling (H_DA). The highest efficiency of dye-sensitized TiO₂ solar cells has been shown by employing Cu complex redox couples. Various groups have reported a fast regeneration rate of oxidized dyes by Cu complexes giving a low driving force attributed to low reorganization energy (λ), but the effect of H_DA has not been evaluated. The values of H_DA and λ can be derived from driving force dependent transient absorption (TA) measurements. However, analyzing TA decay using Cu complexes is not trivial because accelerated recombination by the presence of Cu²⁺ complexes and biphasic TA decay often complicates the analysis. Here we employ 16 Cu¹⁺ and Co²⁺ complexes and two dyes. To simplify the system, i.e., making a minimal electrolyte system, Cu²⁺ and Co³⁺ complexes and a common additive of 4-tert-butylpyridine are not used. From the driving force dependent TA decays of oxidized dyes by both Cu¹⁺ and Co²⁺ complexes, λ for the combination of the Cu complexes and dyes is found to be about 0.15 eV lower than that of Co complexes. Approximately 3 to 5 times higher H_DA values of Cu complexes than those of Co complexes are obtained, which is the dominant factor for faster rates. The values vary with the structure of the molecules, showing the possibility of increasing the H_DA values further. The higher H_DA values of a Cu complex than that of a Co complex are also reproduced by quantum chemical calculations.

中文翻译：

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通过最小电解质系统中驱动力依赖性再生动力学的测量证实了铜络合物和氧化染料之间的高电子耦合

我们确认了铜配合物和氧化有机染料之间的快速再生动力学以及电子耦合（ H _DA）的主要贡献。通过使用Cu络合物氧化还原电对，染料敏化TiO ₂太阳能电池的最高效率已被证明。各个研究小组都报道了 Cu 络合物对氧化染料的快速再生速率，由于重组能 (λ) 较低，驱动力较低，但H _DA的效果尚未得到评估。H _DA和 λ的值可以从驱动力相关的瞬态吸收 (TA) 测量中得出。然而，使用 Cu 络合物分析 TA 衰变并非易事，因为 Cu ²⁺络合物的存在加速重组和双相 TA 衰变通常使分析变得复杂。在这里，我们使用了 16 个 Cu ¹⁺和 Co ²⁺络合物以及两种染料。为了简化系统，即制备最小的电解质系统，不使用Cu ²⁺和Co ^{3+络合物以及4-}叔丁基吡啶的常见添加剂。根据Cu ¹⁺和Co ²⁺络合物对氧化染料的驱动力依赖性TA衰减，发现Cu络合物和染料的组合的λ比Co络合物的λ低约0.15eV。 Cu 配合物的H _DA值比 Co 配合物高约 3 至 5 倍，这是更快速率的主要因素。该值随分子结构的变化而变化，表明进一步提高HD _DA值的可能性。量子化学计算也再现了 Cu 络合物比 Co 络合物更高的H _DA值。